Messages in this thread |  | | Date | Sat, 14 Jul 2001 10:44:47 -0400 | From | jlnance@intrex ... | Subject | Re: RFC: Remove swap file support |
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On Sat, Jul 14, 2001 at 12:07:38AM -0600, Eric W. Biederman wrote: > > The case to watch out for are deadlocks doing things like using > swapfiles on an NFS mount. As you point out we can already do this > with the loop back devices so it isn't really a special case. The > only new case I can see working are swapfiles with holes in them, or > swapfiles that do automatic compression. I doubt those cases are > significant improvements but it looks like they will fall out > naturally.
The case of swap files with holes would be a nice thing to have. It would effectivly give us a way to say "use the extra space on this file system for swap" and at the same time the ability to set a limit on how much space could be taken up by swap. For example you could create a totally sparse 1G file at bootup, and use it as a swap file. If the system needed swap it could grow the file, but you would know that it would never grow beyond 1G.
I dont know if the kernel should punch holes back into the swap file when it no longer needed the space. That would be nice, but it might be a lot of work as I am not sure the VFS supports that. You could accomplish the same thing by having a daemon that added a new swap file every hour and did a swapoff & rm of the old file.
Thanks,
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